Retaining ring for coffee filters



FIG. 1 is a perspective view of a retaining ring for coffee filters showing my new design;

FIG. 2 is a side view thereof, both sides being identical;

FIG. 3 is a top plan view thereof, the bottom being a mirror image;

FIG. 4 is a front view thereof; and

FIG. 5 is a rear view thereof. 

The ornamental design for a retaining ring for coffee filters, as shown. 